void
MaterialPreviewDialog::buildPreviewBitmap( const Ogre::String &texName )
{
const Ogre::uchar BytePerPixel = 8;
// 读取原始image
Ogre::Image *oriImage = getPreviewImage(texName);
// 源大纹理的大小
size_t oriImageHeight = oriImage->getHeight();
size_t oriImageWidth = oriImage->getWidth();
Ogre::uchar *oriImageData = oriImage->getData();
// 分配一个足够大的空间来保存新建的image的数据
size_t newImagegetRowSpan = oriImageWidth*oriImage->getBPP()/BytePerPixel; // 新建的image的行宽（单位为字节）
Ogre::uchar *newImageData = new Ogre::uchar[oriImageHeight*newImagegetRowSpan];
Ogre::uchar *newImageDataPointer = newImageData;
Ogre::uchar *oriImagedataPointer = oriImageData;
// 把所选的纹理的数据提取出来，并创建一个新的image
for ( Ogre::uint i=0; i<oriImageHeight; ++i )
{
memcpy(newImageDataPointer, oriImagedataPointer, newImagegetRowSpan);
newImageDataPointer += newImagegetRowSpan;
oriImagedataPointer += oriImage->getRowSpan();
}
Ogre::Image newImage;
newImage.loadDynamicImage(newImageData,oriImageWidth,oriImageHeight,1,oriImage->getFormat(),true);
// 如果所选纹理大于64*64，就先resize
if ( oriImageWidth > mPreviewImageWidth || oriImageHeight > mPreviewImageHeight )
newImage.resize(mPreviewImageWidth, mPreviewImageHeight);
// 如果有alpha，要与黑白图进行混合
if ( newImage.getHasAlpha() )
{
Ogre::uchar *tempPtr = newImage.getData();
assert (tempPtr);
for ( size_t i=0; i<mPreviewImageHeight; ++i )
for ( size_t j=0; j<mPreviewImageWidth; ++j )
{
// 取出alpha值
float alphaValue = (float)tempPtr[3] / 255.0f;
// 计算出经过alpha混合后的颜色值
unsigned char r = tempPtr[2] * alphaValue;
unsigned char g = tempPtr[1] * alphaValue;
unsigned char b = tempPtr[0] * alphaValue;
// 设置到image中
mCurrentPreviewImage.SetRGB(j,i,r,g,b);
tempPtr += 4;
}
// 要把指针移回到图片数据的
tempPtr -= mPreviewImageHeight * mPreviewImageWidth * 4;
// 设置到缩略图控件中
}
// 没有alpha，就直接拷贝数据
else
{
memcpy ( mCurrentPreviewImage.GetData(), newImage.getData(), newImage.getSize() );
}
}
/* -----------------------------------------------------------------------
| build bullet height field shape and generate ogre mesh from grayscale image
|
| @param in :
| @param out: raw data of height field terrain
| ToDo: adjest grid scale, grid height, local scale, max/min height
----------------------------------------------------------------------- */
bool
buildHeightFieldTerrainFromImage(const Ogre::String& filename,
btDynamicsWorld* dynamicsWorld,
btAlignedObjectArray<btCollisionShape*>& collisionShapes,
void* &data)
{
Ogre::Image img;
try
{
img.load(filename, Ogre::ResourceGroupManager::DEFAULT_RESOURCE_GROUP_NAME);
}
catch(Ogre::Exception err)
{
LOG(err.what());
return false;
}
size_t grid_w = 65, grid_h = 65; // must be (2^N) + 1
size_t grid_max_w = 129, grid_max_h = 129; // must be (2^N) + 1
size_t img_w = img.getWidth();
size_t img_h = img.getHeight();
// validate image size is (2^N) + 1
if ((img_w-1) & (img_w-2)) img_w = grid_w;
if ((img_h-1) & (img_h-2)) img_h = grid_h;
//if (img_w > grid_max_w) img_w = grid_max_w;
//if (img_h > grid_max_h) img_h = grid_max_h;
LOG("LoadImage name=%s, width=%d, height=%d, width^2+1=%d, height^2+1=%d",
filename.c_str(), img.getWidth(), img.getHeight(), img_w, img_h);
img.resize(img_w, img_h);
size_t pixelSize = Ogre::PixelUtil::getNumElemBytes(img.getFormat());
size_t bufSize = img.getSize() / pixelSize;
data = new Ogre::Real[ bufSize ];
Ogre::Real* dest = static_cast<Ogre::Real*>(data);
memset(dest, 0, bufSize);
/*
| @ Notice the alignment problem
| - uchar to float alignment
| - pixel format in bytes as rawdata type, also affects alignment
*/
Ogre::uchar* src = img.getData();
for (size_t i=0;i<bufSize;++i)
{
dest[i] = ((Ogre::Real)src[i * pixelSize] - 127.0f)/16.0f;
}
// parameter
int upAxis = 1;
btScalar gridSpacing = 5.0f;
btScalar gridHeightScale = 0.2f;
btScalar minHeight = -10.0f;
btScalar maxHeight = 10.0f;
btScalar defaultContactProcessingThreshold = BT_LARGE_FLOAT;
btHeightfieldTerrainShape *heightfieldShape =
new btHeightfieldTerrainShape(img_w, img_h,
dest,
gridHeightScale,
minHeight, maxHeight,
upAxis, PHY_FLOAT, false);
btAssert(heightfieldShape && "null heightfield");
// shape
btVector3 localScaling(1.0f, 1.0f, 1.0f);
heightfieldShape->setLocalScaling(localScaling);
collisionShapes.push_back(heightfieldShape);
// rigidBody
btDefaultMotionState* motionState = new btDefaultMotionState(btTransform(btQuaternion(0,0,0,1),btVector3(0,0,0)));
btRigidBody::btRigidBodyConstructionInfo cInfo(0, motionState, heightfieldShape, btVector3(0,0,0));
btRigidBody* rigidBody = new btRigidBody(cInfo);
rigidBody->setContactProcessingThreshold(defaultContactProcessingThreshold);
int flags = rigidBody->getCollisionFlags();
rigidBody->setCollisionFlags(flags | btCollisionObject::CF_DISABLE_VISUALIZE_OBJECT);
dynamicsWorld->addRigidBody(rigidBody);
// add ogre height field mesh
Ogre::SceneManager* sceneMgr = Ogre::Root::getSingletonPtr()->getSceneManager("DefaultSceneManager");
btAssert(sceneMgr);
Ogre::ManualObject* obj = sceneMgr->createManualObject("btHeightFieldEntity");
btVector3 aabbMin, aabbMax;
heightfieldShape->getAabb(btTransform(btQuaternion(0,0,0,1),btVector3(0,0,0)), aabbMin, aabbMax);
btHeightFieldProcessor callback(obj, "DefaultPlane");
heightfieldShape->processAllTriangles(&callback, aabbMin, aabbMax);
sceneMgr->getRootSceneNode()->attachObject(obj);
return true;
}